def change(mylist) :
    mylist.append([1, 2, 3, 4])
    print('函数 mylist = ', mylist)
mylist = [10, 20, 30]
print('调用函数前, 函数外mylist = ', mylist)
change(mylist)
print('调用函数后, 函数外mylist = ', mylist)
